The present invention relates generally to alignment techniques for photographic equipment and more particularly to an alignment technique for use with a photographic enlarger apparatus.
The present invention is an extension of the principles relied upon in Applicant's U.S. Pat. No. 4,733,257, which is incorporated herein by reference. In that patent a technique for aligning (making parallel) the lens and the film planes of a view camera is disclosed. That technique uses a pair of mirror members, each having a mirror body including its own mirrored surface. A first one of the mirror members is confined to fit within the film standard of the view camera in lieu of a film holder so that its mirrored surface faces the lens standard of the camera and coincides or substantially coincides with the camera's film plane. The second mirror member is configured to replace temporarily the camera's lens and lens board which is within its lens standard so that the second mirrored surface faces the film standard and first mirrored surface and coincides with the camera's lens plane. In addition the second mirror member includes a view hole through its mirror body and mirrored surfaces so that the two mirrored surfaces can be viewed from outside the lens standard. At the same time, certain specific indicia is provided on at least one of the mirrored surfaces such that when the mirrored surfaces are viewed through the view-hole of the second mirror member from outside the lens standard, the indicia will take only one of many different forms if the two mirrored surfaces are parallel. In this way, as the indicia is viewed, the lens and film standards can be adjusted to cause the indicia to take on the one particular form, thereby insuring that the mirrored surfaces, and therefore the lens and film planes are indeed parallel.
Applicant has found it not only important to align view cameras in the manner described in his U.S. Pat. No. 4,733,257, but he has also found it to be quite important to align accurately (make parallel) certain planes of enlarger apparatus. More specifically the photographic enlarger apparatus includes an enlarger head assembly, means for supporting the photographic paper and means for supporting the enlarger head assembly.
Typically the means for supporting the photographic paper is an easel, and the enlarger assembly is supported above the plane of the easel. The photographic paper lies on the easel, and as such, the plane of the photographic paper is in the plane of the easel. In circumstances where very large prints must be made, it is not uncommon to dispense with the easel, and then support the photographic paper in a plane some distance from the enlarger head assembly. For example, the enlarger head assembly may be supported on a table, with the photographic paper supported on the floor below the enlarger head assembly. The paper may also be supported on a wall with the enlarger assembly mounted horizontally in alignment with the photographic paper.
Low light conditions may also present problems in operating an alignment apparatus for a photographic enlarger. This would occur, for example, if the alignment apparatus was used in a darkroom illuminated only by a photographic safelight.
In view of the foregoing it is an object of the present invention to provide an accurate and reliable alignment technique to check the parallel relationship between the lens and/or negative planes of a camera assembly forming part of an overall photographic enlarger apparatus and the plane of an easel which is intended to support photographic paper.
Another object of the present invention is to provide an alignment technique of the last mentioned type which is also uncomplicated and economical, and can be readily incorporated into an existing photographic enlarger apparatus.
Still another object of this invention is to provide an alignment technique that does not require making any modifications to an existing photographic enlarger apparatus, but rather uses existing components that are compatible with the apparatus.
A further object of the present invention is to provide an arrangement for adjusting the plane of the easel forming part of the last mentioned photographic enlarger apparatus in order to make the plane parallel with the lens and/or negative planes of the camera assembly.
Another object of the present invention is to provide an alignment technique which may be used independent of the orientation of the photographic enlarger apparatus.
Yet another object of the invention is to provide an alignment technique which may be used under low light conditions.